A quinoline derivative 1-[[[4-(4-fluoro-2-methyl-1H-in dol-5-yl)oxy-6-methoxyquinolin-7-yl]oxy]methyl]cyclopropylamine as represented by the following formula (I) for treatment of neuroendocrine tumors. Also disclosed is an application of the quinoline derivative in preparation of pharmaceutical compositions/medicaments for treatment of tumors, particularly neuroendocrine tumors.